Trem Blocks - Brass vs. Steel

[Stratman]

Callaham says cold rolled steel is the only material to use for trem blocks.

Callaham is not telling specifics! Most steel plate is cold rolled... Some Fender blocks were cast steel, not rolled plate as the originals ones were and was due to 1950's economics.

Metallurgically, clarification of "COLD ROLLED STEEL" is needed, as follows:

Cold rolling is a metalworking process in which metal is deformed by passing it through rollers at a temperature below its recrystallization temperature.

Cold rolling increases the yield strength and hardness of a metal by introducing defects into the metal's crystal structure.

Cold rolling is most often used to decrease the thickness of plate and sheet metal from ingots.

Cold rolled metal is given a rating based on the degree it was cold worked. "Skin-rolled" metal undergoes the least rolling, being compressed only 0.5-1% to harden the surface of the metal and make it more easily workable for later processes. Higher ratings are "quarter hard," "half hard" and "full hard"; in the last of these, the thickness of the metal is reduced by 50%.

Cold rolling of steel is a common manufacturing process. It is often used to form sheet metal. Beverage cans are closed by rolling, and steel food cans are strengthened by rolling ribs into their sides. Rolling mills are commonly used to precisely reduce the thickness of strip and sheet metals.

[octavedoctor]

Thanks for that explanation, Doc. Physics, or science in general, wasn't my best subject but I think I get what you are saying here.

Correct me I'm wrong on this. The more dense, harder and greater mass, the better the block will serve it's purpose. Is that right? Or is it really all dependent on the material used?

That's kind of it, although you can't necessarily get all of those parameters maxed out.

Lead, for example is much more dense than brass, but is too soft and ductile to provide the mechanical support for resonance. That's obviously an extreme example for illustrative purposes, you couldn't even start to make a trem block out of lead.

[octavedoctor]

I think at the time (centuries ago) steel was exotic and expensive, hence brass bells. It's stuck ever since. I don't know if they sound different from steel, or if it's just the tradition of having brass bells.

Well, bells are actually more commonly made of bronze, and cast. Casting a bell in steel is not an easy process. Cast iron can have a good ring to it though. Again, it is all about the way in which the various characteristics of a metal combine with no one parameter being necessarily superior to another. Cast bronze sustains vibration better than cast brass or steel; steel vibrates better than brass under tension because brass doesn't have the tensile strength to reach the tension required to sustain resonance.

Again there are process issues; Stratman has elegantly described how cold rolling alters the metallurgical qualities. Consider a brass shell case. If brass was such a great resonator then a brass shell case from a naval gun of the early part of this century, such as is often found in houses being used as umbrella stands would have a great ring to it, but they never do because the material is chosen for it's ductility.


But that's just rolled brass; cast materials are entirely different again...

[ErikH]

That's kind of it, although you can't necessarily get all of those parameters maxed out.

Lead, for example is much more dense than brass, but is too soft and ductile to provide the mechanical support for resonance. That's obviously an extreme example for illustrative purposes, you couldn't even start to make a trem block out of lead.

Gotcha. Sot it more of a happy balance between the parameters.

Thanks for such a thorough explanation.

[mariosyjp]

Hello,

I have compared the stock zinc block of my MIM strat with GFS steel block and actually the GFS is significantly warmer.

They weight the same. You can even tell the difference by dropping them on the floor, the zinc produces a much higher pitch.